WO2002038941A1

WO2002038941A1 - Accumulator distribution type fuel injection pump

Info

Publication number: WO2002038941A1
Application number: PCT/JP2000/007912
Authority: WO
Inventors: Kenji Shingu
Original assignee: Yanmar Co.,Ltd.
Priority date: 2000-11-09
Filing date: 2000-11-09
Publication date: 2002-05-16
Also published as: CN1455845A; JP4422405B2; DE60022914D1; EP1333173A4; EP1333173B1; EP1333173A1; JPWO2002038941A1; DE60022914T2; CN100494664C; US6516784B1

Abstract

An accumulator distribution type fuel injection pump (1) used as a fuel injection pump for low-pollution diesel engine low in fuel consumption and capable of meeting an exhaust emission control requirements, wherein a high-pressure fuel accumulated in an accumulating chamber (31) is distributedly fed to each cylinder through a distribution shaft (9), functional members forming high-pressure routes such as a plunger (7), an injection control valve (26) for fuel injection control, the accumulating chamber (31), and the distribution shaft (9) are disposed inside a hydraulic base (Hb), and a plunger part for accumulating fuel into the accumulating chamber (31) is installed in the hydraulic base.

Description

Description Accumulated distribution type fuel injection pump Technical field

The present invention relates to a configuration of an electronically controlled pressure-accumulation type distribution fuel injection pump that distributes and supplies high-pressure fuel accumulated in an accumulation chamber to each cylinder by a distribution unit. Background art

In recent years, the emission regulations of diesel engines have become increasingly strict, and there has been a demand for low fuel consumption and reduction of NOX and particulates. Therefore, the fuel injection pressure has been increasing.

As the fuel injection pressure increases, the number of electronically controlled pressure-accumulation fuel injection pumps that can control the injection pressure arbitrarily regardless of the engine speed is increasing.

This pressure-accumulation type fuel injection pump supplies high-pressure fuel accumulated in a pressure accumulation chamber to each cylinder, and is described in, for example, Japanese Patent Application Laid-Open No. 7-509420. In such a pressure accumulating type fuel injection pump, a fuel pressure accumulating chamber, a plunger for high pressure fuel pumping, an injection control valve for fuel injection control, a distribution means for distributing fuel to each cylinder, a pressure control valve, etc. Functional members for forming a high-pressure path to which high pressure is always applied are provided, but these functional members are separately housed in casings such as blocks formed separately.

As described above, since each functional member configured in the separated structure is always subjected to high pressure even at the connection point, it is difficult to secure the strength, and there is a case where the reliability is low such as oil leakage or damage occurs. The structure was also complicated.

Also, in the above-mentioned accumulator type fuel injection pump, a plurality of parts are provided for pumping fuel to the accumulator, and a plurality of plunger parts are provided in parallel in the force axis direction. As a result, the pressure-accumulation type fuel injection pump becomes large and has a complicated structure. Disclosure of the invention

The present invention relates to a pressure-accumulation type distribution type fuel injection pump for distributing high-pressure fuel accumulated in one or a plurality of accumulators to respective cylinders by a distributing means, comprising a plunger, a pressure control valve for pressure control, and a fuel injection control. Functional components that constitute a high-pressure path, such as a fuel injection control valve, a pressure accumulation chamber, and a distribution means, are disposed in a hydrid base. As a result, these components to which a high pressure is constantly applied are arranged in the hydraulic base, and the strength of the high-pressure path can be sufficiently ensured. In addition, the connection between the respective components can be performed by an oil passage formed by a drill hole or the like formed in the hydraulic base, and since there is no need to use a joint part or the like, oil leakage or damage to the piping may occur. No reliability can be improved.

Further, in the present invention, the distribution shaft as the distribution means is arranged in a direction orthogonal to the cam shaft. Thus, the dimension of the fuel injection pump in the camshaft direction can be reduced, and the size of the fuel injection pump can be reduced as a whole. Furthermore, in small engines, the length of the injection pipe leading to the injection nozzle is shortened by taking out the discharge valve above the holder. Therefore, the fuel volume in the injection pipe is reduced, the injection delay is reduced, and the injection rate and the injection timing can be controlled with high accuracy in a wide rotation range.

Further, in the present invention, a distribution shaft as the distribution means is driven by a cam shaft. As a result, the fuel passage from the plunger driven by the camshaft to the discharge valve through the distribution shaft can be shortened, and the fuel volume in the fuel passage can be reduced. By using a solenoid valve such as a pressure control valve, it is possible to achieve high quality injection such as injection rate control such as a small amount of pilot injection and post injection, initial injection rate control, and injection timing control.

Further, the present invention includes one plunger section for accumulating fuel in the accumulator. This will reduce the size of the fuel injection pump. In particular, the number of parts can be reduced, and the structure can be simplified and the cost can be reduced.

In the present invention, a cam for driving the plunger of the plunger portion is formed separately from a cam shaft for supporting the cam. As a result, when the fuel injection pump is formed for a multi-cylinder engine, the curvature of the cam contact surface with the evening pet becomes smaller, and the contact surface pressure on the tappet becomes higher. By forming the cam that comes into contact with the pet at high pressure by using a high surface pressure material such as SKH, SKD, or ceramic, the camshaft is not as strong as the cam, while increasing the wear resistance. The cost can be reduced by using a member made of a material.

Further, in the present invention, a pulse generating member for cylinder discrimination is provided on a cam shaft of the accumulator type distribution type fuel injection pump, and the pulse generating member is formed integrally with the cam. As a result, it is possible to reduce the number of parts by combining the functional members, thereby achieving further cost reduction and downsizing of the fuel injection pump.

Also, the present invention provides a method for distributing fuel by setting a rotational speed of a power shaft for driving a plunger for pumping fuel to the accumulator to be equal to a rotational speed of an engine to which the accumulator type distribution type fuel injection pump is mounted. The rotational speed of the means is half the rotational speed of the engine. As a result, for example, in the case of a four-stroke engine, the number of peaks formed on the cam is half of the number of cylinders, the number of peaks can be reduced, and the cam can be downsized. The number of processing steps for the cam can be reduced. Also, the cam profile can be reduced to half the speed, and the outer peripheral surface of the cam can be formed to be convex toward the outside. A grindstone can be used, the outer peripheral surface can be easily polished during processing, the processing time can be reduced, and the cost can be reduced. Also, the present invention provides the distributing means, wherein the distributing means is driven by a camshaft via a bevel gear, and the number of teeth of the bevel gear on the distributing means side is twice the number of teeth of the bevel gear on the force shaft side. It was done. As a result, the rotation speed of the distributing means can be reduced with a simple configuration and at low cost by rotating the cam shaft. The speed can be half the rolling speed.

Further, the present invention provides a camshaft, wherein both ends of the camshaft are supported by a housing, and a bearing for supporting a peripheral surface of the camshaft on a side opposite to the plunger is disposed near a force center on a center side of the support by the housing. is there. As a result, the load that the camshaft receives from the plunger or the like can be received by the bearing, and the deflection of the camshaft can be suppressed to reduce vibration and noise. Also, the bevel gear can be made smaller, and the fuel injection pump can be downsized as a whole.

Further, in the present invention, a pressure control valve for accumulating pressure and an injection control valve of the plunger section, which are control system functional members, are respectively arranged in a direction perpendicular to a cam shaft. As a result, the dimension of the fuel injection pump in the camshaft direction can be reduced, and the overall size of the fuel injection pump can be reduced. When the camshaft is arranged horizontally, the axes of the pressure accumulating pressure control valve and the injection control valve are vertical, so that the sliding portion of the control valve can be prevented from being unevenly worn.

Further, in the present invention, a pressure control valve for accumulating pressure, a distribution means, and an injection control valve of the plunger section, which are control system functional members, are respectively disposed in a direction perpendicular to the cam shaft. As a result, the dimension of the fuel injection pump in the cam shaft direction can be reduced, and the overall size of the fuel injection pump can be reduced. In addition, when the drum shaft is arranged horizontally, the pressure control valve for pressure accumulation, the distribution means, and the injection control valve have vertical axes, so the sliding parts of the control valve and the distribution shaft part may be unevenly worn. Can be prevented.

Further, in the present invention, the control system functional member is arranged in a cam shaft direction in the order of a plunger part, a distribution means, and an injection control valve. As a result, the dimension of the fuel injection pump in the camshaft direction can be reduced, and the overall size of the fuel injection pump can be reduced.

Further, in the present invention, the plunger section for accumulating pressure, the distribution means, and the injection control valve are arranged in series. As a result, the dimension of the fuel injection pump in the camshaft direction can be reduced, and the overall size of the fuel injection pump can be reduced. Further, in the present invention, the solenoid valve for controlling the pressure of the accumulation chamber of the plunger portion and the solenoid valve for controlling the injection control valve are arranged at the end of the plunger and the end of the injection control valve, respectively. As a result, the dimension of the fuel injection pump in the camshaft direction can be reduced, and the overall size of the fuel injection pump can be reduced. Further, in the present invention, the sliding direction of the sliding member of the control electromagnetic valve is perpendicular to a cam shaft. This produces the following effects. That is, since only one of these control solenoid valves is provided irrespective of the number of cylinders, it is necessary to operate the number of cylinders each time the camshaft rotates once, and it operates at a very high speed. And many operations are required. Further, the control solenoid valve needs to maintain high-precision and severe operation in order to control the injection amount and the injection time with high accuracy. By disposing the valve element, which is the sliding member of the above, so that it slides in a direction substantially perpendicular to the axial direction of the camshaft, uneven wear occurs on the sliding part even at high speed operation or many times of operation. Can be prevented, and durability and reliability can be improved.

Further, in the present invention, a plurality of the pressure accumulation chambers are formed, and the plurality of the pressure accumulation chambers are arranged in parallel with each other. As a result, the oil passage connecting the pressure accumulating chamber and the plunger chamber in which the fuel pumped by the plunger stays can be formed short, and the wasteful volume of the fuel passage can be reduced. It is possible to shorten the pumping time and reduce the horsepower loss. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram showing a state of the fuel injection pump of the present invention at the time of fuel injection, FIG. 2 is a schematic diagram showing a state of the fuel injection pump also at the time of no fuel injection, and FIG. FIG. 4 is a side cross-sectional view showing a fuel injection pump, FIG. 4 is also a front cross-sectional view, FIG. 5 is also a plan view cross-sectional view, and FIG. 6 shows a second embodiment of the fuel injection pump. FIG. 7 is a front sectional view showing a second embodiment of the same fuel injection pump, FIG. 8 is a side sectional view showing a third embodiment of the fuel injection pump, and FIG. FIG. 10 is a front sectional view showing the third embodiment, and FIG. 1 is a schematic diagram showing an engine system equipped with a pump. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail with reference to the accompanying drawings. First, a schematic configuration of the accumulator type distribution type fuel injection pump of the present invention will be described. Figure

As shown in FIG. 1, FIG. 2 and FIGS. 3 to 5, the fuel injection pump 1 configured as a pressure-accumulation type distribution type fuel injection pump is connected to a pressure accumulating chamber 31 in which high-pressure fuel is accumulated, A plunger 7 for pumping the fuel, a distribution shaft 9 for distributing the fuel pumped from the pressure accumulation chamber 31 to the injection nozzles 29 of each cylinder, and the like are provided.

The plunger 7 is vertically slidably driven by the cam 5 formed on the camshaft 4 through the evening pet 11, and the plunger chamber 7 a formed above the plunger 7 is moved through the check valve 28. And is connected to the accumulator 31.

Further, the plunger chamber 7 a is connected to the low-pressure side circuit 32 via a pressure control valve 27.

When the pressure control valve 27 is in the ON state, the plunger chamber 7a is separated from the low-pressure side circuit 32, and when the pressure control valve 27 is in the OFF state, the plunger chamber 7a is communicated with the low-pressure side circuit 32. I have.

The accumulator chamber 31 and the distribution shaft 9 are connected via an injection control valve 26, and the distribution shaft 9 is configured to be able to communicate with the discharge valve 18 of each cylinder connected to the injection nozzle 29. It has been. The pressure accumulating chamber 31 is provided with a pressure sensor 30 for detecting the pressure in the accumulating chamber 31. Further, a safety valve 24 is connected to the pressure accumulating chamber 31, and when the pressure in the pressure accumulating chamber 31 exceeds a certain pressure, the pressure is released to the low pressure side circuit 32. ing.

A lower valve 36a, an upper valve 36c, and a piston 36d are slidably housed in the injection control valve 26, and the lower valve 36a is stored in a pressure accumulating chamber 31 by a spring 37. Is biased to the side.

Further, the injection control valve 26 is configured as a three-way valve. When the lower valve 36 a slides toward the anti-accumulation chamber 31, the accumulation chamber 31 passes through the distribution shaft 9 and the check valve 1. Through 8 When the lower valve 36a slides toward the pressure accumulation chamber 31 on the other hand, the oil passage r7 and the low-pressure side circuit 3 reach the discharge valve 18 via the distribution shaft 9. It is configured so that only 2 communicates.

The end of the injection control valve 26 opposite the pressure accumulation chamber 3 1 is connected to the pilot valve

The connection path 34 is connected to the pressure accumulating chamber 31 via the bypass circuit 33.

The pilot valve 25 disconnects the connection between the connection path 34 and the low-pressure side circuit 32, and the connection path 3 and the low-pressure side circuit when the pilot valve 25 is on.

The connection path 32 and the low voltage side circuit 32 are configured so as to be disconnected when in the off state.

Further, the pilot valve 25, the pressure control valve 27, and the pressure sensor 30 are connected to an electronic control unit (hereinafter, referred to as “ECU”) 20.

In the fuel injection pump 1 configured as described above, the fuel is supplied from the fuel tank into the plunger chamber 7a, and the pressure control valve 27 is controlled by the ECU 20 as shown in FIG. The plunger chamber 7a is separated from the low-pressure side circuit 32 by being turned on, and the fuel in the plunger chamber 7a is compressed by the plunger 7 which is moved upward by the cam 5 to accumulate the pressure in the accumulator chamber 31. To be pumped.

The fuel pumped to the pressure accumulating chamber 31 is prevented from flowing backward by the check valve 28, and the pressure in the accumulating chamber 31 is accumulated as appropriate.

On the other hand, when pressure accumulation is not required, as shown in FIG. 2, the pressure control valve 27 is turned off, and the plunger chamber 7a communicates with the low-pressure circuit 32, and the fuel in the plunger chamber 7a is discharged into the low-pressure side circuit drain. Is done.

Fuel is supplied from the pressure accumulating chamber 31 to the connection path 34 connected to the pressure accumulating chamber 31 by the bypass circuit 33 via the throttle 33a. At the time of fuel injection, the pilot valve 25 of the injection control valve 26 is turned on by the control of the ECU 20 to connect the connection path 34 to the low-pressure side circuit 32, so that the pressure of the connection path 34 decreases. Therefore, the pressing of the piston 36 d of the injection control valve 26 in the direction of the pressure accumulating chamber 31 is released.

Therefore, the lower valve 36a is attached to the anti-accumulation chamber 31 side by the pressure of the accumulation chamber 31. The storage chamber 31 is urged to slide toward the pressure accumulation chamber 31 side, and the pressure accumulation chamber 31 communicates with the distribution shaft 9.

As a result, the fuel in the pressure accumulating chamber 31 is sent to the distribution shaft 9 by pressure, distributed to each cylinder, and discharged from the injection nozzle 29 via the discharge valve 18.

On the other hand, in the fuel-free injection, as shown in FIG. 2, the pilot valve 25 of the injection control valve is turned off by the control of the ECU 20, and the fuel is supplied from the pressure accumulating chamber 31 through the throttle 33a. Since the connection path 34 and the low-pressure side circuit 32 are disconnected, the pressure in the connection path 34 increases due to the supplied fuel, and the piston 36 d of the injection control valve 26 is stored in the pressure accumulation chamber. 3 Pressed to the 1 side.

As a result, the lower valve 36a slides toward the accumulator chamber 31 via the upper valve 36c, the lower valve 36a sits on the seat 36e, and discharges from the injection control valve 26. The oil passages r 6 and r 7 up to the valve 18 communicate with the low-pressure side circuit 32, so that the drain pressure is reached and the injection ends.

The spring 36 b urges the lower valve 36 a toward the accumulator 31, and is a panel for increasing the pressure of the accumulator 31 at startup.

Next, the arrangement of each component of the fuel injection pump 1, such as the plunger 7, the pressure accumulating chamber 31, the distribution shaft 9, the pressure control valve 27, and the pilot valve 25, will be described.

As shown in FIGS. 3 to 5, a camshaft 4 on which a cam 5 is fixed is provided horizontally below the fuel injection pump 1, and one end of the camshaft 4 is connected via a cam bearing 12. It is rotatably supported by the camshaft housing H.

Above the camshaft housing H, a block-shaped hydraulic base Hb, which is a housing for each of the components such as the plunger 7, the pressure accumulating chamber 31, and the distribution shaft 9, is connected.

A plunger 7 is disposed above the cam 5 in a direction substantially orthogonal to the axial direction of the camshaft 4. The plunger 7 is vertically slidably fitted to a plunger barrel 8 fitted to the lick base Hb. At the lower end of the plunger 7, an evening 11 is attached.

7 and evening pet 1 1 are attached downward by urging means such as spring 16 The pet 11 is in contact with the cam 5 so that the plunger 7 reciprocates up and down by the rotation of the cam 5.

The fuel is pumped to the pressure accumulating chamber 31 composed of the plunger 7, the plunger chamber 7a formed above the plunger 7, the pressure control valve 27, the evening pet 11, the cam 5, and the like, and accumulates the fuel. In the present fuel injection pump 1, only one plunger is provided.

Thus, by providing only one plunger, the fuel injection pump 1 can be reduced in size, the number of parts can be reduced, and the structure can be simplified and the cost can be reduced. .

At the upper end of the plunger 7, the pressure control valve 27, which is an electromagnetic valve for controlling fuel pressure feeding by the plunger 7, is disposed. The pressure control valve 27 is, for example, as shown in FIG. Thus, the valve element 27a is disposed so as to slide in a direction substantially perpendicular to the axial direction of the camshaft 4, that is, in a vertical direction. However, the direction in which the pressure control valve 27 is arranged is not limited to a direction that is substantially orthogonal.

Thus, by installing the pressure control valve 27 at the upper end of the plunger 7, the axial dimension of the cam shaft 4 of the fuel injection pump 1 can be reduced, and the fuel injection pump 1 It is possible to reduce the size.

Also, since only one pressure control valve 27 is provided regardless of the number of cylinders, it is necessary to operate the number of cylinders each time the camshaft 4 rotates once, and it operates at a very high speed, and Many operations are required.

Further, the pressure control valve 27 needs to maintain a high-precision severe operation in order to control the pressure of the pressure accumulating chamber 31 with high accuracy. By arranging the valve element 27a to slide in a direction substantially perpendicular to the axial direction of the camshaft 4, uneven wear is prevented from occurring on the sliding part even at high speed operation or many times of operation. To improve durability and reliability.

On the side of the plunger 7, a distributing shaft 9 is disposed in parallel with the plunger 軸, and the distributing shaft 9 is provided with a distributing shaft sleeve fitted on the hydraulic lick base Hb. 10 and rotatably fitted to the lower end of the distribution shaft 9. It is rotationally driven by the distribution drive shaft 39.

The distribution drive shaft 39 and the distribution shaft 9 are arranged in a direction substantially orthogonal to the axial direction of the cam shaft 4, and the distribution drive shaft 39 and the cam shaft 4 are connected by a bevel gear 19. As a result, the distribution shaft 9 can be rotationally driven by the camshaft 4 via the bevel gear 19, and by such an arrangement and configuration, the distribution shaft 9 is distributed from the plunger portion such as the plunger 7 driven by the camshaft 4. It is possible to shorten the fuel passage (the oil passages r 6 and r 7 described below) from the shaft 9 to the discharge valve 18 to reduce the fuel volume in the fuel passage. Using solenoid valves such as the pressure control valve 27, etc., it is possible to improve the quality of the injection, such as injection rate control such as a small amount of pilot injection, post injection, initial injection rate control, and injection timing control. It becomes possible.

In addition, the discharge valves 18 for the number of cylinders are fitted around the distribution shaft 9 in the hydraulic lick base Hb.

In addition, even if the cam shaft 4 and the distribution shaft 9 are not arranged in the orthogonal direction, the above-described effects can be obtained if they are arranged at a certain angle. The injection control valve 26 is fitted to a side portion of the hide lick base Hb on the side opposite to the plunger 7 of the distribution shaft 9, and is disposed in a direction substantially orthogonal to the axial direction of the cam shaft 4. I have. That is, the injection control valve 26 is disposed such that the upper and lower valves 36 c and 36 a slide in a direction substantially orthogonal to the axial direction of the camshaft 4.

The pilot valve 25 is disposed at the upper end of the injection control valve 26. The pilot valve 25 has a valve body 25a in a direction substantially perpendicular to the axial direction of the camshaft 4, that is, It is arranged to slide in the up-down direction.

By installing the pilot valve 25 at the upper end of the injection control valve 26 in this manner, the axial dimension of the camshaft 4 of the fuel injection pump 1 can be reduced, and the entire fuel injection pump 1 can be manufactured. It is possible to reduce the size.

In addition, since only one injection control valve 26 and one pilot valve 25, which is a solenoid valve for control, are provided regardless of the number of cylinders, high-speed operation and multiple operation Can prevent uneven wear on the sliding part. Durability and reliability can be improved.

The plunger 7, the distribution shaft 9, and the injection control valve 26, which are the control system functional members of the fuel injection pump 1, are arranged in the axial direction of the camshaft 4 from one end of the hydraulic lick base Hb. , Distribution shaft 9, and injection control valve 26 in this order.

In this way, by disposing the distribution shaft 9 at the center and arranging the plunger 7, the distribution shaft 9, and the injection control valve 26 in series, the axial dimension of the camshaft 4 of the fuel injection pump 1 is obtained. Therefore, the fuel injection pump 1 can be downsized as a whole.

The pressure sensor 30 for detecting the pressure in the pressure accumulating chamber 31 is attached to one side surface of the lick base Hb.

In addition, even if the plunger 7, the distribution shaft 9, and the injection control valve 26 are not completely arranged in series, for example, one of the plunger 7, the distribution shaft 9, and the injection control valve 26 is placed in series. Even if deviated, the plunger 7, the distribution shaft 9, and the injection control valve 26 may be arranged substantially in series.

A long hole in the axial direction is formed in the hydraulic lick base Hb substantially in parallel with the axial direction of the camshaft 4 to form a pressure accumulation chamber 31. The pressure accumulating chambers 31 are constituted by one or a plurality of pressure accumulating chambers, and are connected to each other by an oil passage formed in the hydraulic base Hb.

One end of a hole of the hydrid base Hb constituting the pressure accumulating chamber 31 is open to the outside, and this opening is closed by the plug 35 or the safety valve 24. For example, of the plurality of accumulators 31, the opening of the hole forming one accumulator 31 is closed by the safety valve 24, and the opening of the hole forming the other accumulator 31 is plugged 35. It is blocked by.

The plurality of accumulator chambers 31 are arranged in parallel with each other, and are arranged near control system functional members such as the plunger 7, the distribution shaft 9, and the injection control valve 26.

In this way, by providing a plurality of pressure accumulation chambers 31 in parallel and arranging them near the control system functional member, an oil passage connecting the pressure accumulation chamber 31 and the plunger chamber 7a (described later) The oil passages r 3 and r 4) can be made shorter, the useless volume of the fuel passage can be reduced, and the fuel pumping time and horsepower loss can be reduced. ing.

Incidentally, the pressure accumulating chamber 31 can be arranged in a direction substantially orthogonal to the axial direction of the camshaft 4, and may be formed not only in a straight line but also in a middle part. In addition, the plurality of pressure accumulating chambers 31 arranged in parallel need not be arranged in a completely parallel state, but may be parallel as viewed from one direction, and may be mutually parallel when viewed from another direction. What is necessary is just to arrange with an angle to some extent. Furthermore, the parallel state when viewed from a certain direction is not necessarily perfectly parallel but may be substantially parallel.

A trochoid pump 6, which is a feed pump driven by the rotation of the camshaft 4 to feed fuel, is attached to one end surface of the camshaft housing H. The fuel stored in the fuel tank by the trochoid pump 6 is supplied through an oil passage r1 formed in the camshaft housing H and an oil passage r2 formed in the hexadrolic base Hb. It is pumped from chamber 27b to plunger chamber 7a. That is, the oil passage r1 and the oil passage extend from the discharge port 6a of the trochoid pump 6 to the fuel supply chamber 27b and further to the plunger chamber 7a of the plunger section connecting the valve element 27a of the pressure control valve 27. It is connected by road r2.

Then, the fuel pumped to the plunger chamber 7a is introduced into the check valve 28 through the oil passage r3, and is led out from the check valve 28 to the pressure accumulation chamber 31 through the oil passage r4. In this way, by mounting the trochoid pump 6 on one end surface of the camshaft housing H and driving the trochoid pump 6 by the camshaft 4, it is not necessary to provide a separate drive shaft for driving the trochoid pump 6, and parts The number of points can be reduced, the structure can be simplified and the cost can be reduced, and the size of the fuel injection pump 1 can be reduced as a whole.

Also, by communicating the oil passage r1 and the oil passage r2 from the discharge port 6a of the trochoid pump 6 to the plunger chamber 7a of the plunger, the trochoid pump 6 can be connected to the plunger without using a pipe member. Fuel can be pumped, simplifying the structure and lowering costs, and preventing pipe breakage and fuel leakage. Can be prevented.

The feed pump for pumping the fuel may be a rotary gear pump or a vane pump other than the trochoid pump 6.

The check valve 28 is fitted in a fitting hole hd formed in the hydraulic base Hb, and a fuel passage piece 51 is fitted in the fitting hole hd below the check valve 28. Fitted.

The oil passage r3 and the oil passage r4 are formed in the fuel passage piece 51. One end of an oil passage r3 formed in the fuel passage piece 51 is connected to an oil passage r3 formed in the hydraulic lick base Hb, and the other end is a fuel inlet of a check valve 28. Connected to 28a. Also, one end of an oil passage r4 formed in the fuel passage piece 51 is connected to a fuel outlet 28b of a check valve 28, and the other end is formed in a hydric base Hb. Connected to oil path r4.

That is, the check valve 28 is connected to the oil passages r 3 and r 4 formed in the hydraulic base Hb and the oil passages r 3 and r 4 formed in the fuel passage piece 51 respectively. Connected through.

Thus, the oil passage r 3 connected to the fuel inlet 28 a of the check valve 28 provided in the hydraulic base H b and the oil passage r 4 connected to the fuel outlet 28 b are formed. The fuel passage piece 51 is formed separately from the hydraulic base Hb.

As a result, it is possible to process and form the oil passage r 3 and the oil passage r 4 through which the high-pressure fuel passes into a single fuel passage piece 51 separate from the hydraulic base Hb. The processing of the roads r3 and r4 can be facilitated, and the number of processing steps can be reduced.

Further, when processing is performed on the fuel passage piece 51 alone, the processing can be performed with higher precision than the hydraulic base Hb, which is a complicated shape and a large-sized member. The mating surface of the check valve 28 with the formation surface of the fuel inlet 28 a and the fuel outlet 28 can also be processed with high precision and ease, and the oil passage r 3 · r 4 through which high-pressure fuel passes It is possible to reliably seal the connection between the fuel inlet and outlet 28a and 28b, and to prevent fuel leakage and the like. The high-pressure fuel delivered to and accumulated in the pressure accumulating chamber 31 is introduced into the injection control valve 26 through the oil passage r 5 depending on the control state of the pilot valve 25 (when the pilot valve 25 is turned on). The fuel is guided from the injection control valve 26 to the distribution shaft 9 through the oil passage r6.

The injection control valve 26 is fitted in a fitting hole hc formed in the hydraulic base Hb, and the fuel passage piece 52 is fitted in the fitting hole hc below the injection control valve 26. Have been.

The oil passage r5 and the oil passage r6 are formed in the fuel passage piece 52. One end of the oil passage r5 formed in the fuel passage piece 52 is connected to the oil passage r5 formed in the hydraulic base Hb, and the other end is connected to the fuel inlet 2 of the injection control valve 26. 6 Connected to a. Further, one end of an oil passage r 6 formed in the fuel passage piece 52 is connected to a fuel outlet 26 b of the injection control valve 26, and the other end is formed in a hydric base rick base H b. Connected to the oil path r 6.

That is, the injection control valve 26 is connected to the oil passages r5 and r6 formed in the hydraulic base Hb and the oil passages r5 and r6 formed in the fuel passage pieces 52, respectively. Connected via

Thus, the oil passage r5 connected to the fuel inlet 26a of the injection control valve 26 provided in the hydraulic base Hb and the oil passage r6 connected to the fuel outlet 26b are formed. However, it is formed in a fuel passage piece 52 formed separately from the hydraulic base Hb.

This makes it possible to process and form the oil passage r5 and the oil passage r6 through which the high-pressure fuel passes into a single fuel passage piece 52 separate from the hydraulic base Rb. The processing of the roads r5 and r6 can be facilitated and the number of processing steps can be reduced.

In addition, when processing is performed on the fuel passage piece 52 alone, since the processing can be performed with higher precision than the hydraulic base Hb, which is a complicated and large-sized member, the fuel passage piece 52 can be processed. The mating surface of the injection control valve 26 with the formation surface of the fuel inlet 26 a and the fuel outlet 26 b can also be processed with high accuracy and ease, and the oil passage r 5 through which the high-pressure fuel passes Check the seal at the connection between r6 and the fuel introduction port 26a It can actually do so, and can prevent fuel leakage and the like.

The fuel delivered to the distribution shaft 9 is guided to the discharge valve 18 through the oil passage r7 corresponding to each cylinder, and is injected from the injection nozzle 29 of each cylinder.

As described above, the plunger 7, the distribution shaft 9, the pressure control valve 27, the check valve 28, the injection control valve 26, and the pressure sensor 30 composing the high pressure path of the fuel in the fuel injection pump 1 are provided. , The safety valve 24, the discharge valve 18, the pilot valve, and the pressure accumulating chamber 31 are all integrated on a hydraulic base Hb composed of one block-shaped member. .

With such a configuration, these components to which a high pressure is constantly applied are arranged in one block-shaped member, and the strength of the high-pressure path can be sufficiently ensured. In addition, the connection between the respective components can be performed by the oil passages r 1, r 2,... Formed by the drill holes and the like formed in the lick base Hb without using joint parts and the like. Therefore, it is possible to improve reliability without oil leakage or damage to piping.

The functional members (plunger barrel 8, distributing shaft sleeve 10) and fuel passage pieces 51, 52, etc. form a high-pressure passage, and are lubricated by shrink-fitting or cold-fitting on the hydrid base Hb. Closely fitted. Further, a low-pressure chamber 15 is formed below the injection control valve 26 and the distribution shaft 9 at the boundary between the hydraulic lick base Hb and the camshaft housing H.

The low-pressure chamber 15 is connected to a low-pressure circuit 32 mainly constituted by a drill hole formed in a lick base Hb, and includes a plunger 7 and a plunger 7 for pumping fuel to the pressure accumulating chamber 31. Fuel that leaks from the fitting gap with the barrel 8 and fuel that leaks from the distribution shaft 9 between the distribution shaft sleeve 10 and the distribution shaft 9 that fits into the fitting hole hb formed in the lick base Hb. The fuel is recovered in the low-pressure chamber 15 and returned to the fuel tank through the low-pressure drain circuit 100.

The outer periphery of the plunger barrel 8 communicates with the low-pressure chamber 15 through a leak return hole r12 formed in the lick base Hb.

In this way, leakage from the high pressure path side, such as the plunger 7 and distribution shaft 9 to the low pressure side By providing a low-pressure chamber 15 as a recovery chamber for the discharged fuel in the hydraulic base Hb and the camshaft housing H that are the housing of the fuel injection pump 1, the injection pressure of the fuel injection pump 1 becomes extremely high. Leakage fuel generated from the high pressure path side can be reliably collected and returned to the fuel tank.

Thus, it is possible to prevent the leaked fuel from being mixed into the camshaft housing H or the lubricating oil of the engine to dilute the lubricating oil.

A drain port 24 a of the safety valve 24 provided in the pressure accumulating chamber 31 is connected to a low-pressure side drain circuit 100 by a communication path r 11 formed of a drill hole formed in the hydraulic base Hb. The fuel discharged from the accumulator 31 through the safety valve 24 is returned to the fuel tank.

By connecting the safety valve 24 and the low-pressure side drain circuit 100 to the communication path r 11 composed of a drilled hole formed in the hydraulic base Hb, the piping member is eliminated. As a result, it has become possible to prevent fuel leakage and reduce costs. Further, instead of the plug 35 closing the opening of the pressure accumulating chamber 31, the opening is closed by a safety valve 24 so that the safety valve 24 has the function of the plug 35. The number of parts is being reduced.

The low pressure chamber 15 may be connected to the suction side port of the trochoid pump 6 so that the fuel recovered in the low pressure chamber 15 is supplied to the trochoid pump 6. The fuel injection pump configured for six cylinders will be described focusing on the configuration of the five cams.

In the fuel injection pump 101 configured for six cylinders shown in FIGS. 6 and 7, the cam 85 is formed in six peaks, and the cam 85 is formed separately from the cam shaft 84. The camshaft 84 in the divided state is attached to the camshaft 84 so as to be integrally rotatable. Further, the cam 85 is formed with a cylinder discriminating pulser 81 for cylinder discrimination.

As described above, in the case of the cam 85 formed for a multi-cylinder, the curvature of the contact surface with the tappet 11 becomes small, and the contact surface pressure on the tappet 11 becomes high. Therefore, in the case of the fuel injection pump 101 configured for a multi-cylinder, the cam 85 and the camshaft 84 are formed separately, and the cam 85 that comes into contact with the evening pet 11 at high pressure is S KH The camshaft 84 is made of a standard material that is not as strong as the cam 85 to reduce costs by using high surface pressure materials such as steel, SKD and ceramics. I have.

Further, the cam 85, which is a high surface pressure material, is formed by a post-processing method such as sintering or MIM to reduce the cost, but the cylinder discriminating pulser 81 is integrated with the cam 85. The fuel injection pump 101 is made smaller by further combining the functional members to further reduce the cost and to reduce the size of the fuel injection pump 101.

Also, a multi-cylinder fuel injection pump can be configured as shown in FIGS.

In the fuel injection pump 201 shown in FIGS. 8 and 9, the distribution shaft 9 is driven by a cam shaft 94 via a bevel gear 19 ′, and the cam shaft 94 has a cam shaft side gear 1. 9 a ′ is fixed, and the distribution drive shaft 39 on the distribution shaft 9 side is fixed with the distribution shaft side gear 19 b ′, and the cam shaft side gear 19 a ′ and the distribution shaft side gear 19 b 'and. Further, the distribution shaft side gear 19 b ′ in this example has twice the number of teeth as the cam shaft side gear 19 a ′.

Further, the camshaft 94 is driven at the same rotation speed as the rotation speed of the engine to which the fuel injection pump 201 is mounted. Therefore, it is driven by the camshaft 94 via the camshaft side gear 19 a ′ and the distribution shaft side gear 19 b ′ having twice the number of teeth of the camshaft side gear 19 a ′. The distribution shaft 9 is driven at half the rotation speed of the cam shaft 94.

Here, the multi-cylinder fuel injection pump 201 is, for example, configured for a six-cylinder engine.In the case of a four-stroke engine, the distribution shaft 9 rotates once while the camshaft 4 rotates twice. The fuel is distributed and supplied to each of the six cylinders once, and the plunger 7 is configured to pump the fuel to the accumulator chamber 31 six times. The cam 95 has three ridges.

That is, in this case, the number of peaks formed on the cam 95 is half the number of cylinders. Thus, in the case of a four-stroke engine, the number of peaks formed on the cam 95 is half the number of cylinders, so that the number of peaks can be reduced and the cam 95 can be downsized. And the number of processing steps for the cam 95 can be reduced.

Also, the cam profile can be reduced to half the speed, and the outer peripheral shape of the cam 95 can be formed to be convex toward the outside, so that when the outer peripheral surface of the cam 95 is machined, A large-diameter grindstone can be used, the outer peripheral surface can be easily polished during processing, the processing time can be reduced, and the cost can be reduced.

Further, since the distribution shaft 9 and the cam shaft 94 are connected by a bevel gear 19 ′, the rotation speed of the distribution shaft 9 is reduced to half the rotation speed of the cam shaft 94 with a simple configuration and low cost. Speed can be.

The distribution shaft side gear 19 b ′ has twice as many teeth as the cam shaft side gear 19 a ′, and the outer diameter of the distribution shaft side gear 19 b ′ is the cam shaft side gear. The outer diameter of the camshaft-side gear 19a 'needs to be reduced in order to reduce the size of the fuel injection pump 201 because it is larger than the outer diameter of 19a'.

If the outer diameter of the camshaft side gear 19 a 'is made smaller, the camshaft 94 becomes smaller in diameter, but the load received by the camshaft 94 from the plunger 7 etc. due to the high E injection of the fuel injection pump 201 If the camshaft 94 is only supported at both ends, the camshaft 94 may be bent.

Therefore, in the fuel injection pump 201 of the present embodiment, a half-split bearing 71 that supports the peripheral surface of the anti-plunger 7 facing the camshaft 94 (the lower side in FIG. 3) is provided by a camshaft. 9 4 It is arranged near the cam 5 on the center side from the support parts at both ends.

This allows the bearing 71 to receive the load that the camshaft 94 receives from the plunger 7 and the like, thereby suppressing deflection of the camshaft 94 and reducing vibration and noise. In addition, the bevel gear 19 'can be made small, and the fuel injection pump 201 can be downsized as a whole.

Next, an engine system equipped with the fuel injection pump 1 will be outlined. As shown in FIG. 10, the fuel injection pump 1 is mounted on the engine E. The ECU 20 in the system includes, in addition to the pressure sensor 30, the pilot valve 25, and the pressure control valve 27, a fuel temperature sensor 68 attached to the fuel injection pump 1 and a camshaft. A cylinder discriminating sensor 62 for discriminating a cylinder by a cylinder discriminating pulsar 61 that rotates integrally with the cylinder 4 is connected.

The ECU 20 also includes a water temperature sensor 66 for detecting the temperature of the cooling water of the engine E, and a rotation speed sensor 64 for detecting the engine rotation speed by a rotation detection pulser 63 that rotates integrally with the crankshaft. A lift sensor 65 for detecting the lift amount of the injection nozzle 29 of each cylinder is also connected.

Further, the ECU 20 is connected to an accelerator sensor 67 and a sensor group 69 for detecting other boost pressure, intake flow rate, intake temperature and the like.

Based on the detected value of the accelerator opening by the accelerator sensor 67, the detected value of the engine speed by the speed sensor 64, the detected value of the pressure in the accumulator chamber 31 by the pressure sensor 30, etc. The operation of the pilot valve 25, the pressure control valve 27, and the like is electrically controlled by 20 to inject fuel from the injection nozzle 29 at an appropriate injection amount, injection timing, and the like.

At this time, the injection nozzle 29 for which fuel injection is to be performed is determined by the cylinder determination sensor 62, and the other fuel temperature sensor 68, the water temperature sensor 66, the lift sensor 65, and the detection value of the sensor group 69 are used. The fuel injection conditions are adjusted appropriately. Further, the ECU 20 is provided with a failure diagnosis function for determining whether or not a failure has occurred in the engine E or the fuel injection pump 1 when there is an abnormality in the detection values of various sensors.

It should be noted that, instead of the cylinder discriminating pulser 61, it is also possible to discriminate the cylinder using a gear or the like interlocked with the camshaft 4 such as a bevel gear 19 or the like. Industrial applicability

The accumulator type distribution type fuel injection pump of the present invention is applicable to a fuel injection pump of a diesel engine, and in particular, is used as a fuel injection pump for a low-pollution engine capable of meeting low fuel consumption and exhaust emission regulations. Are suitable.

Claims

The scope of the claims

1.1. A pressure-accumulation type distribution type fuel injection pump that distributes high-pressure fuel accumulated in one or more accumulation chambers to each cylinder by a distributing means and supplies pressure control valves for plunger pressure control and fuel injection control A pressure accumulation type distribution type fuel injection pump characterized in that functional members constituting a high pressure path, such as an injection control valve, a pressure accumulation chamber, and a distribution means, are disposed in a hydraulic base. .

2. The pressure-accumulation type distribution type fuel injection pump according to claim 1, wherein a distribution shaft as said distribution means is arranged in a direction orthogonal to a cam shaft.

3. The accumulator type distribution type fuel injection pump according to claim 1, wherein a distribution shaft as said distribution means is driven by a cam shaft.

4. The accumulator-type distributed fuel injection pump according to claim 1, wherein one plunger for accumulating fuel in the accumulator is provided.

5. The accumulator-type distributed fuel injection pump according to claim 1, wherein a cam for driving the plunger of the plunger portion is formed separately from a cam shaft for supporting the cam.

6. A pulse generating member for cylinder discrimination is provided on a camshaft of the pressure accumulating type distribution type fuel injection pump, and the pulse generating member is formed integrally with the cam. Accumulation type distribution type fuel injection pump.

7. The rotation speed of the camshaft for driving the plunger for pumping the fuel into the pressure accumulation chamber and the rotation speed of the engine to which the pressure accumulation type distribution type fuel injection pump is mounted, and the rotation speed of the distribution means. Is set to half the speed of the engine. 2. The pressure accumulating distribution type fuel injection pump according to claim 1, wherein:

8. The distribution means is driven by a camshaft via a bevel gear, and the number of teeth of the bevel gear on the distribution means side is twice the number of teeth of the bevel gear on the camshaft side. A pressure accumulating distribution type fuel injection pump according to claim 7.

9. The camshaft is supported at both ends by a housing, and a bearing for supporting a peripheral surface of the camshaft on the side opposite to the plunger is disposed near the cam on the center side of the supporting portion by the housing. The pressure accumulating distribution type fuel injection pump according to claim 7, wherein

10. The accumulator-type distributed fuel according to claim 1, wherein the plunger portion and the injection control valve, which are control system functional members, are respectively arranged in a direction perpendicular to a force axis. Injection pump.

11. The accumulator according to claim 1, wherein the plunger, the distributing means, and the injection control valve, which are control system functional members, are respectively disposed in a direction perpendicular to the camshaft. Type distribution type fuel injection pump.

12. The pressure-accumulation type distribution type fuel injection pump according to claim 11, wherein the control system functional member is arranged in a cam shaft direction in the order of a plunger portion, a distribution means, and an injection control valve. .

13. The accumulator-type distributed fuel injection pump according to claim 12, wherein the plunger, the distribution means, and the injection control valve are arranged in series.

14. The claim, wherein the solenoid valve for controlling the plunger and the solenoid valve for controlling the injection control valve are arranged at an end of the plunger and an end of the injection control valve, respectively. 11. A pressure accumulating distribution type fuel injection pump according to item 11.

15. The accumulator-type distributed fuel injection pump according to claim 14, wherein a sliding direction of the sliding member of the control solenoid valve is a direction perpendicular to a cam shaft.

16. The accumulator-type distributed fuel injection pump according to claim 1, wherein a plurality of the accumulators are formed, and the plurality of accumulators are arranged in parallel with each other.